Explain how to tell the difference between surge marks and bromide drag on negatives and what the cause is. Also, explain the common solution to the problem for both.
Bromide drag vs surge marks???
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- Bromide drag is caused by lack of agitation, when you have gravity pulling down the development byproducts. I have no personal experience with this, quoting from some books I've read.
- Surge marks are caused by excessive agitation, when you have areas on film where the speed of developer flow exceeds others, quite frequently near the perforation holes on 35mm film
Surge marks, as I understand the term, occur at sprocket holes on 35mm film in which agitation is too high. The negatives show dark areas just around sprocket holes, because the developer is moving faster there.
Bromide drag is the result of insufficient agitation, and shows streaks around sharp areas of greater or lesser density.
I don't think that's a complete explanation. I have had surge marks around the perforations a few times, and I was doing nothing out of the ordinary in the way of agitation: a single simple inversion, holding the tank by the top, followed by a tap on the table as I put the tank down. It's what I always do, and I don't usually get these marks.
But here's an example when I did. I got these with a roll of old film, Agfa Röntgen Fluorapid, intended for recording x-ray fluorescent screens. The marks only appear on one edge of the film. Annoyingly, I don't know if that edge was at the bottom of the tank. As I said, I don't usually get this problem, so I suspect this was caused by something to do with the type of film. It's old; dated 1948. I think it's high in silver (and so in bromide). Although my inversions are reasonably vigorous, I did a reduced-agitation method in dilute Rodinal, with inversions at the start, then at one, three, six and twelve minutes, and poured out at twenty minutes.
A guy at Flickr gave me a detailed description of how 'fresh developer squirts through the perforations' and how I ought to be using a gentle figure-of-eight inversion which apparently Ansel Adams recommended (I confess he'd lost me before bringing up Ansel, but it didn't help!). I note that the streaks are streaks of brightness; greater development; so 'fresh developer' makes some sense.
Surge marks are typically density-plus due to irregular, increased flow of developer over the surface of the emulsion. Most common cure is to modify and reduce agitation, depending on the tank/reel/rack system being used.
Bromide drag is typically density-minus due to development byproducts (mainly bromide) moving from an area of high exposure on a negative in a laminar flow pattern. The exhausted developer causes streaking in comparison to adjacent, normal energy developer. The most common cure is to increase and randomize agitation.
Bromide drag is typically density-minus due to development byproducts (mainly bromide) moving from an area of high exposure on a negative in a laminar flow pattern. The exhausted developer causes streaking in comparison to adjacent, normal energy developer. The most common cure is to increase and randomize agitation.
@Dustin McAmera You're right. Thinking from the first principles, the 35mm film perforations should always be adding some disturbance to developer flow. Agitation speed is just an amplifier.
In fact, I think that all 35mm negatives have surge marks on them. It's the degree of their severity that varies.
For example, if you take an extremely thin negative with a scene of a smooth and solid surface, scan it, and then crank up contrast to absurdly high levels, there will almost always be, no matter how faint, the same pattern. What I am saying is that the flow of liquids is never perfect, and every negative has some imprint of those flows, but sometimes they become more visible due to other factors: scene composition, over-agitation, under-exposure, perhaps film age, or al of the above.
In fact, I think that all 35mm negatives have surge marks on them. It's the degree of their severity that varies.
For example, if you take an extremely thin negative with a scene of a smooth and solid surface, scan it, and then crank up contrast to absurdly high levels, there will almost always be, no matter how faint, the same pattern. What I am saying is that the flow of liquids is never perfect, and every negative has some imprint of those flows, but sometimes they become more visible due to other factors: scene composition, over-agitation, under-exposure, perhaps film age, or al of the above.
MattKing
Moderator
Surge marks are most common with 35mm, because the perforations play a role, but they can occur as a result of other factors that create uneven patterns of fluid flow.
As an example, tray development can lead to what is essentially surge marks along the edges of the negatives, due to the higher flow of developer near the tray's sides.
As an example, tray development can lead to what is essentially surge marks along the edges of the negatives, due to the higher flow of developer near the tray's sides.
MattKing
Moderator
Those effects can be minimized y increasing the randomness of agitation. That is why I consider that is a sign of proper agitation when the fluid seems to be tumbling and gurgling through the film. It is also why it is critical that there be enough air above the fluid in the tank - an overly full tank never gurgles.
This is the same film (that is, another roll of the same Fluorapid stuff), exposed at about ISO 25 this time, and developed with HC110, 1/64 for 15 minutes with one inversion every minute. Not very scientific - I changed almost every variable - but I suspect the change that may have made the difference is I developed two rolls together in my two-reel tank; I got the surge marks in a one-reel tank. As you see, I didn't get surge marks here, despite doing more inversions. I think what Matt says is relevant; I think the bigger tank just allows better flow; but I haven't really got evidence.
@MattKing Yep, but I clearly remember reading somewhere that it's impossible to achieve a perfect chemistry flow in a small tank. Expose an entire 35mm roll shooting a grey card, develop and sample its edge with a densitometer. I bet that no matter what you do you'll see density variations consistent with the perforations placement. They will be small, but they should be there.
If you did such a study, I bet you'd find other small imperfections of small-tank development: maybe a systematic difference between the end of the roll in the centre of the spiral and the end at the edge. And an effect along one edge from being adjacent to the floor, with or without perforations.
Yes, you can see usually increased density right at the frame edge. The slight cropping of the viewfinder image that occurs in most SLRs will prevent this from being noticeable in prints or mounted slides.
Thankfully I never had either problem but I thought these examples may help.(taken from the web)
Surge marks and I think it also looks very similar to stress marks.
Bromide drag.
Surge marks and I think it also looks very similar to stress marks.
Bromide drag.
@foc there's a lot going on with those examples. The first one looks like stress marks mostly and not really surge marks. The second looks like insufficient fixing for the most part. Possibly a photographer experimenting with stand development and attempting "stand fixing" as a logical extension (which doesn't work).
I'll see if I can dig up some examples of surge marks later. I *might* be able to find an example of bromide drag, too, but no promises.
I see a lot of talk about the degree of agitation, but this is a simplistic explanation that doesn't explain the empirical results all to well. If you think of this as variance in the degree of turbulence across the film surface, it all starts to make more sense. Turbulence of course is also influenced by the degree of agitation, but it's not the same thing and other factors play a role as well, such as tank and reel geometry, etc.
After all, continuous agitation does not automatically result in surge marks, while the simplistic theory of over-agitation would suggest this.
I'll see if I can dig up some examples of surge marks later. I *might* be able to find an example of bromide drag, too, but no promises.
I see a lot of talk about the degree of agitation, but this is a simplistic explanation that doesn't explain the empirical results all to well. If you think of this as variance in the degree of turbulence across the film surface, it all starts to make more sense. Turbulence of course is also influenced by the degree of agitation, but it's not the same thing and other factors play a role as well, such as tank and reel geometry, etc.
After all, continuous agitation does not automatically result in surge marks, while the simplistic theory of over-agitation would suggest this.
Alright, here's a first example of surge marks along one edge of a 4x5" negative:
The cause here was development in a Mod54 holder inside a Paterson tank. The double surge marks line up with the 'fingers' on the Mod54. Developer used IIRC was Rodinal, probably 1+100, and agitation was 10 fairly gentle turns every minute. Certainly no over-agitation. Note that the marks are plus density and thus, they really are surge marks and not bromide drag. My hypothesis on the origin is that the marks are caused by the turbulence of the 'fingers' of the Mod54 as the developer settles after an agitation cycle. Across the remainder of the sheet, there would have been no turbulence at this stage and instead the developer exhibited a more laminar flow pattern as nothing. Note that developer is always in motion, essentially, but this motion between (especially infrequent) agitation cycles will be quite minimal. A solution here would have been to agitate more frequently so that the turbulence across the entire film area would increase, evening out the result.
This is an example of (most likely) bromide drag:
Note the minus density bands that extend in a gradient from the top edge of the 35mm frame. This was caused by a stand development approach (Ilford Delta 100 in Moersch Finol; a staining developer similar to Pyrocat). The solution here would have been to simply increase agitation.
I also have examples of surge marks on 120 film and 4x5 sheet film caused by reel geometry and a lack of pre-soak in C41 development using Jobo reels and a CPE2 rotary processor. I'd have to dig these up and scan them, though. In this case, a pre-soak helped me to get rid of these problems, and also switching from the 2509 4x5 reel to the 2509N reel with the anti-surge 'flaps'. My theory on the utility of a pre-soak here relies on witnessing how film behaves as it's being wetted. If you dunk a sheet of film in developer in a tray and start agitating it, you might notice how part of the sheet tends to almost repel the developer, while in other parts the developer penetrates the emulsion more evenly. If no pre-soak is used, this means that there are differences in activity of the developer especially in the first 30 seconds of development. The brief time of C41 development exacerbates any differences in development that arise at this stage, but also with B&W the effects can be visible under certain conditions. Alternative solutions here would be to alter reel geometry, depart from rotary development altogether and use inversion agitation instead (although this can have its own problems, too; see first example above) or to use an entirely different approach towards development (e.g. dip & dunk, possibly augmented with nitrogen burst agitation).
Since the mechanisms behind especially surge marks are quite varied and boil down to complex flow patterns, the possible solutions are also quite diverse. In my view, they should be dealt with on a case by case basis and by carefully observing the exact pattern of unevenness and using that as a basis to form a hypothesis of the factors causing the problems. A solution can then be based on this. This is also why seemingly contrary advice can sometimes be encountered (one person suggesting to increase agitation while another suggests the exact opposite). They may even both be right - but you'd have to take other factors of their suggestion into account, such as agitation dynamics/approach, reel & tank geometry, the film, developer etc. - and many of these are often left implicit.
The above is IMO just scratching the surface of a fairly complex topic and that's why I can sometimes be a bit gruff or dismissive if I see people simplify the issue of surge marks and their contributing causes, and/or conflating surge marks and bromide drag.
The cause here was development in a Mod54 holder inside a Paterson tank. The double surge marks line up with the 'fingers' on the Mod54. Developer used IIRC was Rodinal, probably 1+100, and agitation was 10 fairly gentle turns every minute. Certainly no over-agitation. Note that the marks are plus density and thus, they really are surge marks and not bromide drag. My hypothesis on the origin is that the marks are caused by the turbulence of the 'fingers' of the Mod54 as the developer settles after an agitation cycle. Across the remainder of the sheet, there would have been no turbulence at this stage and instead the developer exhibited a more laminar flow pattern as nothing. Note that developer is always in motion, essentially, but this motion between (especially infrequent) agitation cycles will be quite minimal. A solution here would have been to agitate more frequently so that the turbulence across the entire film area would increase, evening out the result.
This is an example of (most likely) bromide drag:
Note the minus density bands that extend in a gradient from the top edge of the 35mm frame. This was caused by a stand development approach (Ilford Delta 100 in Moersch Finol; a staining developer similar to Pyrocat). The solution here would have been to simply increase agitation.
I also have examples of surge marks on 120 film and 4x5 sheet film caused by reel geometry and a lack of pre-soak in C41 development using Jobo reels and a CPE2 rotary processor. I'd have to dig these up and scan them, though. In this case, a pre-soak helped me to get rid of these problems, and also switching from the 2509 4x5 reel to the 2509N reel with the anti-surge 'flaps'. My theory on the utility of a pre-soak here relies on witnessing how film behaves as it's being wetted. If you dunk a sheet of film in developer in a tray and start agitating it, you might notice how part of the sheet tends to almost repel the developer, while in other parts the developer penetrates the emulsion more evenly. If no pre-soak is used, this means that there are differences in activity of the developer especially in the first 30 seconds of development. The brief time of C41 development exacerbates any differences in development that arise at this stage, but also with B&W the effects can be visible under certain conditions. Alternative solutions here would be to alter reel geometry, depart from rotary development altogether and use inversion agitation instead (although this can have its own problems, too; see first example above) or to use an entirely different approach towards development (e.g. dip & dunk, possibly augmented with nitrogen burst agitation).
Since the mechanisms behind especially surge marks are quite varied and boil down to complex flow patterns, the possible solutions are also quite diverse. In my view, they should be dealt with on a case by case basis and by carefully observing the exact pattern of unevenness and using that as a basis to form a hypothesis of the factors causing the problems. A solution can then be based on this. This is also why seemingly contrary advice can sometimes be encountered (one person suggesting to increase agitation while another suggests the exact opposite). They may even both be right - but you'd have to take other factors of their suggestion into account, such as agitation dynamics/approach, reel & tank geometry, the film, developer etc. - and many of these are often left implicit.
The above is IMO just scratching the surface of a fairly complex topic and that's why I can sometimes be a bit gruff or dismissive if I see people simplify the issue of surge marks and their contributing causes, and/or conflating surge marks and bromide drag.
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Although “surge marks” and “bromide drag” are not specifically named, they are addressed in the following excerpt (which has been previously posted in other discussions).
Page 12: Agitation of the Developer
Agitation is probably the least understood and the most abused of all the developing controls, even though it is a crucial process that should be used for consistent and uniform results. When agitation is lacking, a stagnant layer of developer and development by-products forms at the interface of the emulsion and the solution. This stagnant layer is partly depleted in the developing agent and is rich in bromide from the developing emulsion. Since bromide is a restrainer that inhibits developing action, the rate of development is retarded unless fresh developer is supplied to the emulsion. On the other hand, if the developing solution is properly agitated, fresh solution is continually brought into contact with the emulsion, and the normal development rate prevails.
Lack of agitation also contributes to another processing problem. Without agitation, the stagnant layer, which is heavier than the fresh developing solution, begins to sink slowly to the bottom of the processing vessel. As it sinks, it tends to leave streaks on the processed negative. Good agitation overcomes this tendency toward uneven development.
Line and point images are subject to several adjacency effects, that can, in part, be traced to insufficient agitation. Such effects often show up as excessively dark edges, or as low-density halos outside dense images. The effects are usually minimized by vigorous agitation throughout development.
In general, proper agitation is most important for the initial stages of development. That is the time that the gelatin is swelling and development is just beginning. Unevenness in the distribution of fresh developer at this time usually causes rather severe effects.
Agitation techniques vary, and the particular method used will depend on the manner of development. Agitation should always consist of movements that will not cause a current of solution to flow constantly in any one direction. Such currents are the cause of increased density.
Black and White Processing Using Kodak Chemicals
Eastman Kodak 1985, No. J-1, CAT NO 152 8462, LOC 82-71447, ISBN 0-87985-312-3Page 12: Agitation of the Developer
Agitation is probably the least understood and the most abused of all the developing controls, even though it is a crucial process that should be used for consistent and uniform results. When agitation is lacking, a stagnant layer of developer and development by-products forms at the interface of the emulsion and the solution. This stagnant layer is partly depleted in the developing agent and is rich in bromide from the developing emulsion. Since bromide is a restrainer that inhibits developing action, the rate of development is retarded unless fresh developer is supplied to the emulsion. On the other hand, if the developing solution is properly agitated, fresh solution is continually brought into contact with the emulsion, and the normal development rate prevails.
Lack of agitation also contributes to another processing problem. Without agitation, the stagnant layer, which is heavier than the fresh developing solution, begins to sink slowly to the bottom of the processing vessel. As it sinks, it tends to leave streaks on the processed negative. Good agitation overcomes this tendency toward uneven development.
Line and point images are subject to several adjacency effects, that can, in part, be traced to insufficient agitation. Such effects often show up as excessively dark edges, or as low-density halos outside dense images. The effects are usually minimized by vigorous agitation throughout development.
In general, proper agitation is most important for the initial stages of development. That is the time that the gelatin is swelling and development is just beginning. Unevenness in the distribution of fresh developer at this time usually causes rather severe effects.
Agitation techniques vary, and the particular method used will depend on the manner of development. Agitation should always consist of movements that will not cause a current of solution to flow constantly in any one direction. Such currents are the cause of increased density.
This is worth emphasizing, regardless of one's philosophy of amount and type of agitation.
I attribute my successful use of SRA (Somewhat Reduced Agitation) to three minutes of steady random inversion to start.
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